Grommet



Apri! 18, 1944.

F. E. McGEE GROMMET FiledMarch 9, 1942 I STWQYVI'DD Francis HM: B EE- Patented Apr. 18, 1944 UNITED STATES PATENT OFFICE GROMMET Francis E. McGee, Baltimore, Md. Application -March 9, 1942, Serial No. 433,932

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 O. G. 757) 1 Claim.

The invention described herein maybe manu factured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to a protector for the A desirable grommet should possess the dual-' ities of easy application combined with the security of attachment and ease of removal. Fur thermore, in times of vast production it becomes increasingly desirable to utilize an article which is simple of manufacture and economical of' essential raw materials. With respect to the security of attachments, the loading and shipping of projectiles subjects them necessarily to a great deal of abuse, this being of small consequence to the shell proper, but often proving fatal to the soft and precisely dimensioned rifling rings. The known grommets have not proved equal to such hazards because of a tendency to compromise with ease of application and removal. With respect to the latter, it is essential that gunners in the field be able to remove the grommets in any and all conditions of illumination or weather and often to do so without removing their gloves.

Another drawback of known grommets is the space they require for shipment from the factory. This is obviated in the present invention by making the grommets in separable parts whereby they may be nested. These parts are assembled into a hinged grommet which is easily placed about the riiiing rings.

It is therefore an object of the invention to provide a grommet of sturdy construction, fabricated of inexpensive, plentiful materials, which shall be easy to ship, assemble and apply, certain of protection when applied and easy to remove at will.

To these and other ends, the invention consists in the construction, arrangement and combination of elements described hereinafter and pointed out in the claim forming a part of this specification.

A practical embodiment of the invention is illustrated in the accompanying drawing wherein:

Figure 1 i a top plan View of a preferred embodiment.

Figure 2 is a fragmentary view in elevation showing the hinge of Fig. 1.

' Figure 3 is a fragmentary view in elevation showing the fastener of Figure 1.

Figure 4 is a section taken on the line 4-4 of Figure l.

Figures 5 and 6 are views similar to Figure 3 showing modifications.

Figures 7 and 8 are views similar to Figure 2 showing modifications.

Figure 9 is a top plan view of the hinge of Figure 8. v

Figure 10 is a broken elevation'alview of a half section of a modified grommet, and

Figure 11 i a broken top plan; view showing the join of two such members as in Figure 9, and

Figure 12 is a fragmentary view showing a modification of the fastener of Figure'3.

Referring to the drawing by characters of reference there is shown a grommet having outer semicircular bands I of sheet steel or any durable metal or other material having inturned flanges 2 forming an inner circumferential channel. Received in the channel between flanges 2 and secured as by rivets 3 or any other suitable means are resilient members 4 which may be cotton webbing, rubber, pressed paper, lignon or any other suitable material, the list here given not 7 be slipped on or off the projectile without straining against a natural and considerable arcuate resiliency and may be nested for shipping whether already hinged or separate.

The hinge shown in the preferred form comprises a U-shaped pin 5 engaging in loops 6 formed by turning back the ends of shield I.

For the fastening means, arched portions I are struck outward at the termini of the shields l opposite the hinge portions. The arches I are struck in line with a previously formed perforation 8 which may be made by punching, and which serves as a passage for a threading means such as the wire 9. The arch 1 has its rear slope intersecting the span of the perforation 8 whereby the latter is raised on a slant from the surface of shield l to facilitate easy threading,

B ur fastening the grommets, a wire is simply inserted through the arches 1 and twisted in any :onvenient manner for retention therein. Any )ther known form of securing means may be used vnstead of the wire, such as a cotter pin or spring :lip.

A better distribution of the clamping force nay be attained by provision of additional arches I a shown in Figures 5 and 6. In this case the arches are shown as merely struck, without the perforations 8 added.

Securement against lateral displacement while an the rifling band is provided for by flanges 9a at the sides of the resilient member which overlap the extremities of the rifiing band and by intermediate rib I designed to fit into a gas check groove in the band, it being understood that th pattern may be varied to Suit any parbicular rifling band.

A simply constructed type of grommet of easy application is shown in Figures '10 and 11. A band II is formed with a tongue I 2 and a slot l3 nearby, and a slot l4 at the opposite end slightly raised to form bridges l5 and 16 constituting receiving means for a-tongue such as I2. The bridge l6 may be entirelystruck from the band II to leave a slot. A grommet may be formed of a single such band II or of any desired number, since they may be attached.- chain fashion. The band II in the case of a grommet of a single unit is wrapped around the projectile, passed through the slots M at .the other extremity of the band, wrapped .back on itself and secured in slots 13. The single band type does not have the advantages of the hinged type but if two or more units are attached by means of a tongue fastened through the slots I4 on the next succeeding unit, the tongue joint will-serve as a hinge. The units ll may be made very short and used in proper multiples to fit various sizes of shells. This will solve a production problem having to do with the number of types necessary to provide for in fabricating, storing, shipping and issuing. In the case of a short unit I l, in addition, the curvature may be dispensed with, since-small tangent members will approximate a true circumference and also by this means adjustment is possible to bring an integral number of units into engagement with any projectile regardless of size.

A simple hinge such as shown in Figure 8 :with a short tongue I! passed through a slot !8 in the adjacent band may be employed in any hinged type described herein. The advantage of this type as well as that of Figure 2 is that it is capable of repeated flexing without fatigue.

.However, since repeated flexing will seldom be encountered, the simpler types such as that of Figure 7 will in general sufiice.

In order to smooth the circumferential profile of the protector as an aid in shipping andto do away with annoyance, delay and injury to the users, the regions having the fastening means and hingesmay be located ina depression in the armor I as shown in Figure 12.

'I claim:

A component for rifling bands of projectiles comprising a strip, a tongue on one end of said strip, a pair of parallel slits crosswise of the strip, one near the tongue and of a lengthto receive the width of the tongue and a similar ,35 slitin the, end of the strip opposite the tongue carrying end, the tongue attached to ,the slit remote from the tongue and bent back and passed through the adjacent slit in its own strip.

FRANCIS E.,McGEE. 

